Interval control mechanism



Oct. 22, 1946. I E. L. KENT 2,409,941

INTERVAL CONTROL MECHANISM Filed Jan. 5, 1944 (Eg Qui I i,

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Patented Oct. 22, 1946 INTERVAL CONTROL .MECHAN ISM Earlc L. Kent, Elkhart, Ind., assignor'toC. G.

Conn, Ltd., Elkhart, Ind.,

Indiana :av corporation of Applicationianuary 5, 1944, serial'No. 517,025

oi. .zoo- 33) 7 Claims. l This-invention relates to -interval control mechanism and more particularly to switching mechanism for supplying an electrical impulse of ypredetermined duration.

One of the objects of the invention is to provideinterval rcontrol mechanism in which the duration of 'anl electrical impulse can be -accurately adusted-. In the constructionyshown the duration of an impulse can be adjusted in fractions of a micro second.

Another object is to provide interval control mechanism in which duration of an impulse is determined by a pair of spaced brushes moving over a contact drum. Adjustment of theinterval is laccomplished in this construction by advjusting the relative positions of the brushes to vary the time both brushes engage a conducting portion of the drum.

Still another object of the invention is to provide interval control mechanism in which safety means are provided to prevent closing a circuit between the brushes during resetting of the mechanism.

The above and other objects and advantages will be more readily apparent from the following description when read in connection with the-accompanying drawing, in which- Figure l is a plan lview of an intervalV control mechanism embodying the invention; and

Figures 2 and 3 are partial -diagrammatic views show-ing the mechanism in different positions.

4 The apparatus shown in Figure 1 comprises a base lo on which is mounted an electric motor H. The motor is preferably a synchronous or constant speed motor of sufficient power to drive the apparatus without any substantial variation inspeed during the cycle of operations. As shown, the motor may be controlledby a switch 12.

The motor shaft carries at its outer end a drum: l-3 'as shown in Figures 2 and 3 formed with insulatedl end portions vM and a conducting central portion |5. The several portions of the drum are connected along helical lines l6 terminating in abrupt shoulders Il. While the drum has been shown with the ends of insulating materialand the centerV portion of conducting material, it will be--understoodthat this arrangement could be reversed.

A- carriage is provided movable axially of the drum and as shown in Figure 1 is formed/by a sleeve IB fitting over the drum. The sleeve carries a pair of spaced brushes one indicated at 19 being fixed in the-sleeve and'the otherfshown at 20-being carried by a kcollar 21 which is threaded on the sleeve. The-threads connecting thercollar 2| -to the sleeve are preferably of the same axial pitch as the helical lines l6.

The carriage is held against rotation while being permitted to move axially of the drum by a pair of arms 22 pivoted to the carriage at one end 2 vand attheir opposite ends pivoted to a blockv 23 -on the base. These arms being parallel serve to -guide the carriage and hold it against rotation while permitting it v'to move along the drum.

In operation-the drum is rotated and the y'carriage is moved along i't from initial position shown in Figure '2 to a final position shown in Figure 3. Inthe initial position the brush [39 engages the conducting portion l5 of the drum, while the brush 20 engages the insulating portion I'4 at one end of the drum. Asthe carriage is moved-axially of the drum, the brush 2'6 will pass across the shoulder FIi on to the conducting portion l5 to establish a circuit between the brushes. 'This circuit will be maintai-ned until the leading brush 19 movesacross the shoulder ll at the right end of the drum to interrupt the circuit. Thus the interval during which the circuit is maintained will depend upon the relativ-e positions of the brushes. I

In order to adjust the brush Z-U-to provide the desiredV interva-l, the collar 2| is Aformed at one end withscale markings having calibrations 24 thereon for one scale indication and calibr-ations 25 fora second scale indication. Preferably the two scale indicationsv are in different Vcolors so that they may be readily distinguished. One of the scale indications cooperates With a reference mark 26 on the sleeve IB and the second scale indications cooperate with a similarV axially spaced mark 21. The marks 26 and 21 may be colored to correspond to the scales for easy reading. As the collaris turned indications are first obtained on the scale 24 opposite the reference mark 26, the reference mark 21 at this time being spaced axially from the collar. As the collar is turned-further it moves up on the reference mark 27 and the interval may then be read opposite this mark on the scale 25. The scales are preferably-calibrated in micro seconds so that the interval can 'be-adjusted accurately in fractions of a second.

The carriage is moved along the drum by a feeding mechanism including a cylindrical feed member-28 on the motor shaft having plain cylindrical end portions 28. with a helical thread 29 therebetween. The pitch of the thread 29 is the, same as that of the helical lines l6 so that as the carriage is advanced the brushes will move parallel to the lines 16.

The ycarriage has pivoted thereon a lever 3| which carries at one end a follower pin 32 adapted tojengage the threads 29 to advance the carriage. V'I'helever 3I-may be normally urged in va position to engage the feed member by a spring orv thelike not shown and may bev moved out of engagement withl the feed memberby al handle' 33V onA the end'ofth'elever.

The carriage is shown in Figure 1 in its initial position in which the follower pin 32 engages the cylindrical portion 28 to the left of the threads 29. The carriage is urged toward the threads by a spring 34 and is held in its initial position against a spring tension by a latch 35. Preferably, adjustable stops 36 and 31 are provided to limit the initial and final positions of the carriage.

'I'o operate the mechanism with its carriage in initial position as shown in Figure 1 and with the motor I l running, the latch 35 is released. The spring 34 then moves the carriage to the right until the follower pin 32 engages the threads 29. The carriage will continue to move at a rate determined by the threads to close a circuit between the brushes IS and 20 for a predetermined interval as explained above. When the carriage has moved over against the stop member 31 the follower pin 32 will ride on 'the Cylindrical portion 23 at the right of the feed member.

To reset the mechanism the lever 3| is swung clockwise to raise the follower pin 32 above the point where it will engage the threads 29. The carriage will then be moved to the left until the latch 35 is engaged at which time it is set for another operation.

In order to prevent accidental Completion of a circuit between the brushes during resetting, a switch 38 is provided on the carriage in circuit with the brushes. The switch 38 is normally closed but is engaged by the lever 3I when it is operated to move the follower finger away from the feed member to be opened. Thus, during resetting it is impossible to establish a circuit through the brushes.

While one embodiment of the invention has been shown and described in detail herein, it is understood that this is for the purpose of illustration only and is not to be taken as definition of the scope of the invention, reference being had to the appended claims for this purpose.

What is Claimed is:

1. Interval control mechanism comprising a) rotatable contact drum having adjacent conducting and insulating portions joined along helical lines, a carriage movable axially of the drum. means to move the carriage at a substantially constant rate, a pair of spaced brushes on the carriage engageable with the drum, and means mounting one of the brushes on the carriage for adjustment about the drum axis along helical lines having the same axial pitch as the first named helical lines to vary the helical distance around the drum surface between the brushes.

2. Interval control mechanism comprising a rotatable contact drum having adjacent conducting and insulating portions joined along helical lines, a carriage movable axially of the drum, a feed screw rotatable with the drum having the same axial pitch as said helical lines, means on the carriage engageable with the feed screw to move the carriage axially of the drum, a pair of brushes on the carriage engageable with the drum, and means mounting one of the brushes on the carriage for adjustment around the drum in a helical path having the same axial pitch as the feed screw and said helical lines.

3. Interval control mechanism Comprisng a rotatable contact drum having adjacent conducting and insulating portions joined along helical lines, a carriage movable axially of the drum, a feed screw rotatable with the drum having the same axial pitch as said helical lines, means on the carriage engageable with the feed screw to move the carriage axially of the drum, a pair of brushes on the carriage engageable With the drum, a collar threaded on the carriage coaxial with the drum Carrying one of the brushes, the threaded connection between the collar and carriage having the same axial pitch as the feed screw and said helical lines.

4. Interval control mechanism comprising a rotatable contact drum having adjacent conducting and insulating portions joined along helical lines, a carriage movable axially of the drum, a feed screw rotatable with the drum having the same axial pitch as said helical lines, means of the carriage engageable with the feed screw to move the carriage axially of the drum. a pair of brushes on the carriage engageable with the drum, a collar threaded on the carriage coaxial With the drum carrying one of the brushes, the threaded connection between the collar and carriage having the same axial pitch as the feed screw and said helical lines, the collar having a pair of graduated scales at one end, and a pair of axially spaced index marks on the carriage cooperating with said scales respectively to indicate the interval during which the brushes are electrically connected through the drum.

5. Interval control mechanism Comprising a contact drum having conducting and insulating portions, a carriage movable axially of the drum, a pair of spaced Contacts carried by the carriage engageable with the drum, a feed screw aligned with the drum, a follower movably mounted on the carriage engageable With the feed screw to move the carriage along the drum, and a switch in circuit with the Contacts engaged and opened by the follower when it is moved out of engagement with the feed screw.

6. Interval control mechanism comprising a contact drum having conducting and insulating portions, a carriage movable axially of the drum, a pair of spaced Contacts carried by the carriage engageable with the drum, a feed screw aligned with the drum, a lever pivoted on the carriage and carrying at one end a follower engageable with the feed screw to move the carriage along the drum, and a switch on the carriage in circuit with the Contacts engaged and opened by the lever When it is swung to a position to disengage the follower from the feed screw.

'7. Interval control mechanism comprising a shaft rotatable at a substantlally constant speed, a Contact drum on the shaft having Conducting and insulating portions joined by helical lines, a carriage movable longitudinally of the drum, Contacts on the carriage engaging the drum, a collar threaded on the carriage coaxial with the drum on threads having the same axial pitch as said helical lines and carrying one of the contacts, a feed member on the shaft having cylindrical ends and a helical thread between them of the same axial pitch as said helical lines, a follower pivotally mounted on the carriage movable into engagement with the feed member, a switch in circuit with the Contacts opened by the follower when it is moved out of engagement with the feed member, a latch for holding the carriage in one end position, and resillient means urging the carriage toward its other end position.

- EARLE L. KENT. 

